Pay question of course

Can someone explain this to me pls lol, in January I’ve been off work due to being poorly from the 17/01/2025 to the 31-01-2025 I work 22.5hours per week, I put a sick note in dated 21/01/2025 to 31-01-2025 but I’ve been unpaid sick pay 67.5 hours I don’t understand why is this actually all correct?